Effect of sintering temperature on the structural disorder and its influence on electromechanical properties of the morphotropic phase boundary composition 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT)

We have investigated the effect of sintering temperature on the microstructure, crystal structure, dielectric, ferroelectric, and piezoelectric properties of the morphotropic phase boundary (MPB) composition lead-free piezoelectric 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT). We have found that the specimen sintered at an optimized temperature (1150 °C) exhibits the maximum piezoelectric response (d33 ~ 198 pC/N). The maximum piezoresponse is associated with the presence of optimized structural disorder amidst long-range ferroelectric order in the poled state of the specimen. The structural disorder in the present case is caused by the propensity for stabilizing in-phase octahedral tilt.